Grinding machine work sizing mechanism



Ct- 31 1944 c. G. FLYGARE ET AL 2,361,833

GRINDING MACHINE WORK SIZING MECHANISM Filed Sept. 23, 1945 4SheetS-Sheet l Caf@ GU? 5161,76. Wan/i A esm.

(Ittomeg Ocf- 31, 1944 c. G. FLYGARE ET AL 2,361,833

GRINDING MACHINE WORK SIZING MECHANISM Filed Sept. 25, 1945 4Sheets-Sheet 2 Oct. 31, 1944. c. G. FLYGARE ETAL 2,361,833

y GRINDING MACHINE WORK SIZING MECHANISM Filed Sept. 23, 1943 4Sheets-Sheet 5 Oct. 31, 1944. Q Q FLYGARE ET AL 2,361,833

GRINDING MACHINE WORK SIZING MECHANISM Caf? GHz/gare. F'fanln A.Heam/om,

Patented Oct. 3l, 1944 GBSINDING MACHINE WORK SIZING MECHANISM Carl G.Flygare, Worcester, and Frank A. Helstrom, Lexington, Mas., assignors toNorton Company, Worcester, Mass., a corporation of MassachusettsApplication September 23, 1943, Serial No. 503,514

(Cl. lil-165) 7 Claims.

This invention relates to grinding machines and more particularly to thewheel feeding and truing mechanisms of a grinding machine.

Various problems are involved in grinding du plicate cylindricalsurfaces. and particularly on a single piece of work, where it is oftennecessary `to true the grinding wheel before the several work surfaceshave been finished. For example, the hub of an airplane propeller blademay have a set of ball raceways ground thereon by means of a formedgrinding wheel. Buch a wheel requires frequent truing in order tomaintain its shape. When the wheel has been trued. it is necessary tofeed the grinding wheel forward to a new final position in order to sizethe work as required. Measurement of the work size for this purpose isoften diflicult and time wasting. Moreover, various types of apparatusused for truing the grinding wheels of standard cylindrical grindingmachines are not applicable for truing the wheel used for grinding thehub of a propeller blade because of the necessity for leaving the bladein position until all of the raceways have been ground. For example, itis customary to true the wheel at the point of contact with the work,such as in a plain cylindrical grinding machine in which the wheel isrun oli! the work and against the diamond ad1aeent to the end of thework where the diamond is positioned in alignment with the grinding lineof contact. This construction is not feasible in a machine of the typeshown in the drawings or in other types of grinding machines where thegrinding wheel must be 4 backed off to true the work before it grinds asecond surface on the same work piece.

The primary object of this invention is to overcome such problems asthese and to provide a grinding machine with a wheel feeding mechanismin association with a truing device and indicator mechanism whichinsures that two work surfaces may be ground to identical radialdimensions before and after the grinding wheel has been trued. n

A further object of the invention is to provide a truing and indicatingmechanism which is so constructed and arranged that an tindicating gaugemay be used once and for all to indicate the final position of thegrinding wheel when the work has been ground to the required size, andwhereby the grinding wheel may be fed forward after a truing operationto a point indicated by that single dial setting.

A further object of the invention is to provide a grinding machine inwhich an indicating mechanism is so constructed in association with awheel truing device that the relation of the indicating mechanism to thewheel feeding mechanism remains the same during the life of the grindingwheel, and wherein the indicator may be set to a given scale markingafter the machine is set up for a grinding operation and the indicatorneed not be changed when the grinding wheel is trued or during theperiod of grinding duplicate work diameters. Further objects will beapparent in the following disclosure.

This invention is applicable to the various types of grinding machines,but it is herein illustrated as-applied to a machine especially adaptedfor grinding a set of parallel spaced raceways on the cylindrical hub ofan airplane propeller blade. as is required for feathering the rbladeduring its operation.

Referring to the drawings:

Fig. 1 is a vertical elevation of the machine, with parts broken away toshow details of construction;

Fig. 2 is a top plan view of the machine with parts broken away to showthe work supporting slide and elevating mechanism;

Fig. 3 is an enlarged sectional detail of the wheel truing andindicating mechanisms;

Fig. 4 is a vertical sectional view on the line 4 4 of Fis. 3;

Fig. 5 is a view taken on approximately the line l-i of Fig. 3, partsbeing broken away for clarity of illustration; and

Fig. 6 is afragmentary detail showing the tru ing tool slide vandoperating mechanism.

In accordance with the illustrated embodiment of this invention, agrinding wheel is mounted on a slide arranged to feed the whel intothe\work. A diamond truing tool is mounted on a second slide carried bythe iirstslida. and it is arranged to feed the diamond forward againstthe wheel at a point which is 180 from the line of grinding contact withthe work. A dial gauge or other suitable indicator is mounted on astationary portion of the base. The position of the line of grindingcontact with the work may be indicated by suitably setting this gauge,and the extent of forward feed of the wheel towards the work is measuredthereby. The truing tool is connected to the dial gauge by means of alever of the first class which is pivoted on the lower slide. One arm ofthis lever is connected to the upper slide carrying the diamond, and thelower arm of the lever operates the dial. The two effective lengths ofthe lever arms are exactly equal; hence the forward movement of thewheel slide to compensate for truing the wheel causes the gauge toregister the same reading for a given work size irrespective of anyreduction in Wheel size.

As shown in the drawings, the grinding machine comprises mechanism forsupporting the propeller blade Ill in a vertical position so that it maybe ground by a grinding wheel Il. The blade is mounted for rotationabout the axial line of its cylindrical hub I2. The grinding wheel II issuitably mounted on a vertical shaft I3 which is axially parallel withthe work axis. Suitable power mechanism may be provided for rotating thegrinding wheel shaft. such as a standard electric motor I4 of a constantspeed type. The wheel and motor shaft is supported in suitable radialand end thrust bearings, and the vertical position of the wheel isthereby accurately determined. The grinding wheel support, including theelectric motor, is mounted on a wheel slide I5, which in turn isslidably mounted on suitable horizontal ways I8 on the machine base Il.The wheel is axially immovable, or not movable vertically along itsaxis, but it may be moved by the slide towards and from the work withits side faces lying always in the same parallel planes.

The wheel slide may be moved by suitable or standard construction. Asshown, the under side of the wheel slide is provided with a half nut I8engaging the threads of a large screw I8; and the latter is adapted tobe rotated by a suitable micrometer mechanism for manually adjusting theposition of the grinding wheel. The screw I9 is supported at one end ona small shaft suitably mounted in bearings in the framework. This shaftcarries a bevel gear 2| meshing with another gear 22 on one end of ashort cross shaft which has fixed on its other end a. gear 23 meshingwith a further gear 24 on the micrometer hand wheel shaft. The handwheel 25 and the associated micrometer mechanism 26 serve to turn thegear 24, and this moves the wheel slide precisely to an extent measuredby the micrometer or until a stop on the micrometer strikes the pawl 2`Ithrown into its path. All of this may be of standard construction. Theright hand end of the screw I9 is carried on a large bearing member 28suitably mounted in the machine. This construction may be made accordingto the U. S. patent to Wood No. 2,294,- 872 of September 1, 1942. Ifdesired, the wheel slide may be moved hydraulically by power mechanismsuch as that shown in the U. S. patent to Cole No. 2,283,792 of May 19,1942.

The propeller blade or other work piece is held rigidly in a verticalposition in axial parallelism with the wheel. The work is mounted tc beboth rotated and adjusted vertically. It is clamped by suitablemechanism in axially alignment with a rotatable, vertically adjustablesupport 30. This support is carried by a shaft 32 which is suitablymounted in thrust and radial bearings carried in a hollow slide casing34. The lower reduced end 26 of the shaft I2 is slidably keyed withinthe hub of a pulley 31 suitably suspended in bearings 3l on thehorizontal frame member 39 of the machine frame. The pulley is rotatedat a desired slow rate by a belt leading from an electric or othersuitable type of motor 40 mounted on the outside of the machine base.

Provision is made for moving the work vertically along its axis andrelative to the grinding Wheel, so that the axially immovable wheel maygrind a series of parallel ball raceways. To this end, the casing 34isprovided with two aligned,

laterally projecting slide members or flanges 42 (Fig. 2) which bearagainst the vertical slide faces 43 formed on a wall 44 constructed as apart of the machine base. The slide flanges are held in place by meansof gibs 4I secured by screws to the wall 44.

The casing 34 and associated parts are supported on the top of a hollowframe having spaced, parallel side walls 41 and a horizontal bottomportion 4l. The latter carries a threaded bushing 48 which is threadedonto the vertical jack screw 50 supported in suitable bearings II at thebase of the machine. The jack screw I0 carries near its lower end a gear52 keyed thereto. This gear meshes with a gear Il on a suitablysupported vertical shaft 54 which carries at its upper end a worm gearl. meshing with a worm on a horizontal shaft B4 to which is affixed ahand wheel l1. By turning the hand wheel, the screw 5l will be threadedthrough the bushing 4l and thus will adjust the supporting framevertically and locate the propeller blade carried thereby. The axis ofthe lifting screw is preferably located in vertical alignment with thecenter of the mass of the propeller and the supporting slide, as shownin Fig. 1. Various features of this machine are describedvand claimed inthe copending application Serial No. 498,950 filed August 17, 1943.

The grinding wheel may be trued to the required shape by a truingmechanism of suitable construction, such as one made in accordance withthe patent to Grimng #2,056,149 issued September 29, 1936. As shownparticularly in Fig. 5 a diamond l0 is set to project from the end o! ametal holder Il which is slidably mounted in a swinging cradle I2 forendwise movement toward and from the grinding wheel. The slldable holder4I has a large head II at its outer end and a compression spring 44 ismounted between this head and a wall of a recess within the cradle andso arranged as to tend to withdraw the diamond from contact with thegrinding wheel. The diamond is held forward against the grinding wheeland its slidable movement is determined by means of a form bar or camwhich engages a projecting tip Il of the diamond holder 4I. This formbar ll is so shaped that as the diamond is rocked back and forth byswinging the cradle 42, the diamond 4I will be moved to shape thecylindrical surface of the grinding wheel as required to make the ballraceway groove on the propeller shaft.

Both the cradle l2 and the form bar Il are carriedlon a slide 10 whichis slidably mounted on a framework carried by the lower slide II andarranged to move the diamond toward and from the wheel. The slide hasdepending from its lower side two diverging arms 12 which are connectedthrough spaced Journal boxes 1I with two lower arms 14. A form barsupport 'Il also hangs from the slide and connects the upper and lowerarms 12 and I4 at intermediate points. This support has two spacedcurved ribs 'II forming a groove within which the form bar ll isremovably mounted. Various strengthening ribs Il are ar ranged on, thesupport 'I4 to hold the form bar rigidly in place.

The swinging cradle I2 is suitably mounted within the Journal boxes Ilon end pivots and II. A handle 83 connects with one pivot and serves torock the cradle as required. This rocking motion traverses the diamondacross one wheel face. The diamond moves in and out in accordance withthe shape of the form bar 65.

registers on the dial gauge.

pivoted to the outside of the casing walls 81 and are adapted to beswung up into slots on the flanges 82 of the cover and thus clamp thecover in position. This permits the cover to be swung up and thus tomove the diamond and form bar f to positions where they, may be removedor inspected. The slide 10 is held in position by means of gibs 95 (Fig.4) suitably secured, as by screws, to the under side of the cover 86.kThe slide 10 is made sufficiently short so that it may be moved back andforward as desired for truing the wheel.

In order that the slide may be moved manually, it is provided with anupstanding flange which is threaded to form a nut |00. This carries ascrew (Fig. 3), and the reduced end |02 of this screw is supported onsuitable ball bearings in a housing |03 carried on the cover 86. Aspiral gear |04 on the end of this shaft |0| connects with another gear|105 keyed on a shaft |06 which is suitably mounted on a bracket |01carried by the casing walls 81. A micrometer dial |06 (Fig. 6) isarranged on the outer end of the shaft for turning the screw |0| througha measured distance and thus moving the slide that carries the diamond.By manipulating the micrometer |08 and the handle 63, the diamond may becaused to true the surface of the grinding wheel.

In the use of the machine, the grinding wheel is fed forward to grindone of the ball raceway grooves on the propeller blade. Ordinarily, themicrometer mechanism 26 is moved to set a stop carried by the hand wheel25 at a required distance from the pawl 21, so that the grinding wheelmaybe fed forward until the stop engages the pawl, thus indicating thatthe wheel has been moved through the required number of thousandths ofaninch for the grinding operation. Ifthe Wheel is trued after one of theball raceways has been ground, then it is necessary to reset themicrometer mechanism by a distance equal to the decrease in radius ofthe grinding wheel when trued by the diamond. v

In order to indicate the distance through which the diamond has beenmoved and by which the grinding wheel must be fed forward to give thesame depth of cut, I have mounted a standard dial gauge ||0 on astationary pedestal fixed on the machine base (Fig. 1). A sliding bar||2 is suitably mounted in and slides through supports ||3 projectinglaterally fromthe wheel slide I5. This bar may contact with and operatethe plunger ||4 of the dial gauge. The bar ||2 moves horizontally in thedirection of the wheel slide movement, and any movement of the slide Apin I6 projecting laterally from the bar ||2 rides between the yoke`ends of a swinging lever ||6` which is mounted on the pivot shaft Thisshaft is suitably mounted in bearings ||8 on the top of the wheel slide|5. At the inner end of this shaft is an upstanding lever arm |20. Thetop of this lever arm is also shaped to form a yoke, and between thefingers of the yoke rides a pin |22 which projects laterally from theform bar support 16. The pin |22 moves with the slide |0 and the diamondand therefore may serve to measure the decrease in radius of the Wheelwhen trued. The

effective lengths Aof the arms ||6 and |20 are made exactly the same.That is, the pins ||5 and |22 are equi-distant from the axis'of theshaft and thus any movement of the pin |22 forward with the diamondsupporting slide moves the lower pin' 5 and the slide bar ||2 backthrough the same distance. This causes the plunger of the dial I0 tomove through the same distance, andthus indicate the decrease in wheelsize when it is trued.

When a new grinding wheel is put into place on the machine, the zero`position of the dial gauge ||0 is determined and set oncey amifor all,so as to give ja required depth of cut in the work and produce thedesired ball raceways. When the work positionis to be changed to grind anew groove, the grinding wheel is backed away from the work, thus movingthe bar ||2 from engagement with the dial gauge. The work is adjustedvertically as described, and again the grinding wheelis fed forward intocontact with the work and the grinding proceeds until the dial gaugeagain registers zero. If the wheel is to be trued, the diamond slide 10and the pivot pin |22 are moved forward during truing, and the pin ||5and the slide bar ||2 Whicii operates the plunger of the dial moveforward equally. In order that the grinding wheel of reduced size may-grind to thesame depth of cut, the operator must now useth'e micrometermechanism 26 to feed the wheel forward through the exact distance thatit was decreased in radial size. The

` forward feeding movement of the wheel slide I5 causes the axis of thepivot shaft and the pin |22 to move equally; hence the swinging arm |6travels parallel with itself. That is, if the pin |22 has been movedforward by 5 thousandths of one inch, this moves the slide bar ||2 awayfrom the dial to the same extent. Then the wheel-slide must be moved up0.005 before the dial will register zero, as before. Thus the indicatingmechanism compensates automatically for a reduction in wheel size due totruing or normal wear of the wheel. This condition is brought about bythe fact that the dial gauge ||0 is stationary on the wheel base, thepivot shaft is mounted on the lower slide |6 and the pin |22 is on theupper slide 10. Thus the lever arm ||6 moves parallel with itself as thewheel slide I5 is moved in and out and the dial ||0 indicates the nalgrinding position. When the wheel is trued, the

lever arm ||6 tilts to a different angle and the bar ||2 moves backthrough the same distance as represents the reduction in wheel size.Thereafter the arm ||6 moves parallel with itself as the wheel slide ismoved, and the latter must be moved up to an additional extent asrepresented by the reduction in wheel size before the dial gauge ||0will indicate zero. Hence the dial shows the final grinding position ofthe wheel at all times, irrespective of wheel wear.

It will now be appreciated that the sizing apparatus above described maycompensate for the ordinary wheel wear when the work is being sized.That is, if the wheel has worn to a smaller diameter and the diamond ismoved up until it just touches the wheel, the rocking leverautomatically moves the dial gauge bar ||2 back through an equaldistance. Then the wheel slide will have to be fed forward by that samedistance to make the dial gauge register the predetermined reading, suchas zero, Which indicates that the work has been ground to the requiredfinal size. The forward movement of the pivot of the rocking lever isthe same as the reduction in radius of the wheel, whether caused bywheel wear or truing or both. Hence, the diamond may be moved tocorrespond with a reduction in wheel size, and this movementautomatically requires that the wheel be fed forward through the samedistance before the dial gauge will give its zero reading.

It will be understood that these general principles of work sizing areapplicable to any type of grinding machine which has a grinding wheelsupport and a work support that are relatively movable towards eachother to feed the wheel into the work. The pivot of the rocking lever ismounted on the movable support, the dial or other type of gauge employedis stationary, the gauge is operated by one arm of the lever, and theother arm is arranged to be moved in correspondence with a reduction inwheel wear.

It will also be appreciated that various mechanical equivalents may besubstituted for the rocking lever with its equal arms; or othermechanical elements may be used in association to give the same resultsas above described. The lever or equivalent mechanism is such that themember which operates the size indicating device, such as the dialgauge, is moved through a distance that is proportional to the reductionin wheel diameter, and the parts are so arranged that the wheel must befed towards the work through a distance which compensates for the lossin wheel size before the indicating mechanlsm will give the same finalreading as before to indicate a given Work size.

Hence, the above disclosure is to be interpreted as explaining theprinciples of my invention and as describing a preferred embodimentthereof and not as imposing limitations on the appended claims.

We claim:

1. A grinding machine comprising a work support, a grinding wheel, asupport for the wheel. means for moving the supports relatively towardseach other to feed the wheel into the work, a stationary gauge whichindicates work size, a device movable forward independently of saidsupports to a position determined by a reduction in the wheel radius, amember for operating the gauge, and mechanism which moves said memberaway from the gauge by a distance proportional to the forward movementof said device and which requires feeding the wheel towards the workthrough a distance equal to the reduction in wheel radius so as to givea predetermined gauge reading for a given work size.

2. A grinding machine comprising a work support, a grinding wheel, asupport for the wheel,-

means for moving said supports relatively to feed the wheel into theWork, a device movable independently of said supports to touch theeffective surface of the wheel at a point which is 180 from the point ofwork grinding contact, a stationary work size indicating gauge, a membercarried by the movable support which operates the gauge, and meansconnecting said device and member which moves the latter away from thegauge through a distance that is proportional to the forward movement ofthe device as required to touch the wheel, said parts being so arrangedthat when the wheel is fed towards the work said member is moved forwardthrough a distance equal to any reduction in wheel radius to give apredetermined fixed gauge reading for a given work size.

3. In a grinding machine having a work support and a grinding wheel togrind the work, a

s,sei,ess

'wheel truing and work sizing mechanism comprlsing a grinding wheelslide, means to feed the slide to grind the work, a truing tool, a toolslide on the wheel slide for feeding the tool to true the wheel. astationary size indicating cause. and a lever having its effective armsof equal lengthl which is pivotally mounted on the wheel slide, one armbeing connected to move forward with the truing tool and the other armbeing connected to operate the gauge, said parts being so arranged thatthe gauge registers a predetermined reading for a given work siseirrespective of any decrease in wheel size due to truing the wheel.

4. In a grinding machine having a work support and a grinding wheel togrind the work, a wheel truing and work sizing mechanism comprising astationary base, a wheel slide on the base, means to feed the slide togrind the work, a truing tool, a truing tool slide on the wheel slidemovable to true the wheel at a point which is from the grinding point, astationary sise indicating gauge mounted on the base, a lever having itseffective arms of equal length which is pivotally mounted on the wheelslide, one arm being movable forward with the truing tool slide as thetruing tool is fed forward to true the wheel, and the other arm beingconnected to operate the gauge, and means for moving the truing toolslide, said parts being so arranged that the gauge registers apredetermined reading for a given work size irrespective of any forwardmovement of the slides as required to true the wheel and feed the wheelto grind the work 5. A grinding machine comprising a base, a worksupporting slide, a grinding wheel, a wheel slide, means to move thework parallel with the wheel axis, means for moving the wheel slide iofeed the wheel into the work, a stationary indicating gauge mounted onthe base, a lever pivotally mounted on the wheel slide which has itseffective arms of equal lengths. one arm being connected to operate thegauge, and means whereby the other arm may move in correspond- I encewith a reduction in wheel size, said parts being so arranged that thegauge registers a predetermined reading for a given work sizeirrespective of any decrease in wheel size.

6. A grinding machine comprising a base. a work slide thereon, arotatable work support on the slide, a grinding wheel, a grinding wheelslide on the base which is movable to feed the wheel into the work, atruing tool, a mount for moving the tool forward to true the wheel at spoint which is 180 from the point of work grinding contact, a sizeindicating gauge nxed on the base,A a member for operating the gauge, alever having its effective arms of equal lengths which is pivotallymounted on the wheel slide, a connecting means whereby one arm movesforward with the truing tool, the other lever arm being connected tomove said member away from the gauge through a distance equal to theforward movement of the tool, and means for moving the wheel slideforward which moves the lever and truing tool in a fixed relation sothat the gauge automatically registers a predetermined reading for agiven work size irrespective of any indeterminate reduction ln wheelsize.

7. A grinding machine comprising a base, a work slide mounted thereonfor vertical slidable movement, a rotatable work support on the slide, agrinding wheel having a vertical axis, a wheel slide carrying the wheeland movable to feed the wheel horizontally towards the work, a sizeindi- 2,se1,sss 5 moved by the yother arm which operates the gauge andis moved away from the same when the tool moves forward, said partsbeing so arranged that the gauge gives a. predetermined reading for agiven work size irrespective of any 5 f reduction in wheel size.

CARL d. FLYGARE. FRANK A. Hmls'rRoM.

